Internal expansion brake



Dec..30, 1930. G. H. STONER 1,786,461

INTERNAL EXPANSION BRAKE Filed July 13 192 Patented Dec. 30, 1930.

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CORPORATION" 01' IASSLCE'UQETTS ETERNAL EIPANSION BRAKE Application fled July 13, 1927. Serial Io. 805,477.

. illustrated them with reference to what might be called the two-shoe type of brake. In my present application I shall deal more particularly with internal brakes involving more.

than two shoes and more specifically with a brake of the three-shoe type, although it-also involves a flexing shoe feature which is related but independent.

While my invention is not to be limited to a three-shoe brake, that type will bo shown and discussed as ityillustrates certain roblems involved and certain solutions o ered by my invention. Previous principles of adjustment of curvature apply in part as heretofore'set forth inmy previous patents, and in part enterdnto certain new combinations as will be hereinafter described. In the drawmgs: v r

Fig. 1 is a viewof a brake in accordance with my present invention in elevation and disposed within its drum. Fig. 2 is a plan view partly in section of a bracket coupling for adjustment between shoes. ,7

Fig. 3 is a rider.

Fig. 4 a fragmentary section through an intermediate shoe strut, and Fig. 5 a diagrammatic view showing in somewhat exaggerated form for purposes of illustration the flattening of the lower intermediate brake sector when the braking force is applied. 1

Referring to the drawings I have indicated at 1 a drum of conventional design. Within this I are mounted shoe members 2 and 2a which-are preferably of the flexibletype adjustable to curvature b the strut rods which subtend them as chor s as described in my previous patents. As herein shown the strut rods'are of two formsl Those subtending the terminal shoes consists of strut or chord members 3 extensible by. a reversely threaded memher 4 screwed into their ends and locked by nuts 4 At the cam I member 3 is pivoted as at 5 in a bracket 6 sectionthrough the anchor pin end of these shoes the strut having)a face 7 which is kept up against the cam 8 y a tension spring 9. At the opposite end of the terminal shoes the strut members 3 are pivoted as at 5 in a bracket 10 within which is pivoted a tap ed hinge 11 receivin one end of the threa ed connection 12 an held by thelock nut 13. I

The hinged connections between the'shoes comprising the hinge piece 11 and the threaded connection 12 constitute a double hinge or' double pivoted link by reason of which the intermed ate shoe 2a has a certain radial freedom as well as a freedom of end movement which permits it to flatten slightly under the pressure transmitted by the other shoes or through their strut members. The action is somewhat of a toggling nature and the result is that the intermediate shoe can be made to find the drumand to exert an equalizing pressure In doing so it willbe noted that it can move slightly radially and be slightly straightened under the resultant force trans mitted when the cam 8 is operated.

v The opposite end of. this connection 12 is tapped into a corresponding bracket member to which is. ivote'd one end of a strut or chord member 0 slightly dilferent construction. This member is shown in section inv Fig. 4 and consists of a sleeve portion 14L within which a reduced stem 15 of a slidin member 16 is re.-v ceived. The small spring 1 may be confined within the member 14 and bearing against the end 15 in order to insure clearing motion, although the resiliency of the subtending shoe is under normal conditions sufiicient to accommodate for play. Into this member 16 is tapped the eye bolt 18' which is pivoted in the usual manner at 5 to the adjacent bracket 10 at the opposite end of the shoe.

It will therefore be seen that this strut member for-the bottom or intermediate shoe 2a is capable of being. freely elongated by the intermediate shoe 2a in expanding and of being positively elongated by turning up on the member 16 to flatten the curvature of the intermediate shoe 2a where such is de sired for. adjustment.

In the form shown *I provide an anchor pin casting 19 slotted at 19 to receive the anchor pin P. 4 The casting 19 has a vertical bore within which is mounted a shoe or rider 20 yieldingly held down by a spring 21 confined by aplug 22 held by a cotter-pin 23. This member 19 which is riveted to the intermediate shoe 2a therefore supports the three shoe members of the brake on the anchor pin P out of contact with the drum. When, however, the cam 8 is actuated and the terminal shoes 2 are forced outwardly, the resultant thrust through the connections 12 give a togaction which tends not only to force t e intermediate shoe 2a downward but has a tendency to flatten it out. In practice this toggling action is ver slight and I have therefore illustrated t is feature diagrammatically in Fig. 5, in which the members 12 are shown as thrusting outwardly on the shoe 2a in considerable exaggeration.

It will therefore be seen that the intermediate shoe 2a can, where desired, be given a slightl shorter radius in adjustment over the terminal shoes so as to be independently flexed at the desired phase of brake application and thus give a positive and r0 essive setting to the intermediate shoe. t t e same time a resultant back pressure is established on the terminal shoes. Furthermore, these pressures are developed with substantial uniormity on both the downward and upward rotative bases of the drum and whether the rotation is ahead or in reverse.

The initial adjustment of the shoes through the subtending chord or'strut members is effected in the usual way by a plying a span-' ner to the member 4 by lengt ening or shortening the effective length of the members 3 so that any desired initial curvature may be attained or so as to take up for any wear that malyhoccur on the lining L.

e principles herein involved are capable of various embodiments and the shoes may obviously be multiplied in number by subdivision of the shoe members or the brake might be provided with a single continuous flexible shoe member where segmental adj ustment was not desired. All such modificationsand variants are understood to be with in the purview of my invention.

What I therefore claim and desire to secure by Letters Patent is: 1. In a brake, a. pair of shoes and an intermediate shoe pivotally linked to each and a radially yieldable mount for the intermediate shoe m sustaining relation thereto.

2, In a brake, a pair of shoe members and an interposed shoe member pivotallly linked] to each and having a radially yields. 1.. bearing for the anchor pin. I

3. In a brake, a pair of shoe members and an interposed shoe member pivotally linked to each and a spring pressed radially acting anchor pin shoe adapted'to bear on the anchor in.

4. 11 an internal expansion brake, a flexible shoe member and a subtending strut therefor, said strut having a positive ad'ustment longitudinally and a free longitu inal extensibility independently thereof.

5. In an internal expansion brake, a flexible shoe member and a subtending strut therefor, including a threaded coupling for positive adjustment and a slidingmember per= missive of longitudinal expansion independent thereof. a

6. In an internal expansion brake, a pair of shoe members, a pressure transmitting connection betweenthe two, one of said shoes being flexible and means on said flexible shoe for maintaining a predetermined minimum radius of curvature while ermissive of increasure upon pressure 0 said radius of curvature. I

7. In an internal expansion brake, 'a shoe system including an interposed flexible shoe member, means for positively controlling the contractive tendency, and connections in the shoe system, and effective u on their ex ansion to give a flattening resu tant to the exible shoe.

8. In an internal expansion brake, a shoe system including a flexible shoe member, means for positively controllin the contractive,tendency, and hinged lin connections between the flexible shoe and the adjacent shoes efiective to expand the flexible shoe.

9. In an internal expansion brake, a shoe system including an interposed flexible shoe member, and connections in the shoe system, efl'ective upon their expansion to give a flattening resultant to the flexible shoe.

10. In an internal expansion brake, a shoe system including a plurality of flexible shoe members, a radially movable pivotal support for said members, a cam for operating said 'shoe members, and a rigid backing for each of said shoe members disposed in pressure transmitting r: lation from the cam through the shoe system.

11. In a brake of the class described, an

expansion member comprising a pair of terminal shoes and an intermediate shoe adapted to contact the brake drum, adjusting connections between and hinged to the ends of the intermediate shoe and the adjacent ends of the terminal shoes, respectively, and a floating spring sustained support for said intermediate brake shoe permissive of movement radially of the brake drum, and means for expanding the shoes within said drum.

12. In a brake of the class described, an expansion member comprising a pair of terminal shoes and an intermediate shoe adapted to contact with the brake drum, adjusting connections between and hinged to the ends of the intermediate shoe and the adjacent ends of the terminal shoes, respectively, an anchor pin rider on the intermediate shoe for yieldabiy supporting said brake shoe permissive of movement radially of the brake drum, and

of the terminal shoes, respectively, and a floating support for said brake shoes permissive of movement radially of the brake drum,

and means for expanding the shoes within said drum.

In testimony whereof I aflix my si nature.

GEORGE H. STO R. 

